The Department of Health said a number of EU countries have made similar decisions.
The National Immunisation Advisory Committee (NIAC) has recommended that all currently authorised Covid-19 vaccines can be used in adults of all ages, including those aged 70 years and older.
However, NIAC has also recommended that mRNA vaccines - Pfizer/BioNTech and Moderna - should be used for the over 70’s where practicable and timely.
A number of other European countries have announced similar plans which will see over 70s receive the mRNA vaccines where possible.
The advice from NIAC to the Minister for Health recognised there is currently limited data on the AstraZeneca vaccine in relation to older age groups.
“The main objective of the vaccination strategy is to prevent morbidity and mortality," Chief Medical Officer Dr Tony Holohan said.
"International and national data indicate that those aged 70 years and older are at significantly higher risk of hospitalisation and mortality.
"Due to the demonstrated efficacy of mRNA vaccines in older persons and in recognition of their particular vulnerability in terms of their increased risk of death and serious disease if they contract Covid-19, it has been recommended that mRNA vaccines be administered to all those over 70 years in order to provide the highest level of protection available to this population.”
Supplies of AstraZeneca will begin arriving in Ireland from next week and deliveries of Pfizer and Moderna are ongoing.
